Vascular anchoring device

ABSTRACT

In a vascular anchoring device intended to be introduced into a blood vessel by a catheter and including braces ( 2 ) that are expandable in the radial direction, the anchoring device is formed by a substantially hollow-cylindrical part ( 1 ) including axially extending braces ( 2 ) departing from an end side, and a locking member ( 3 ) coaxially guided within the hollow-cylindrical part ( 1 ) along a guide wire ( 4 ) of the catheter. The locking member ( 3 ) carries at least one ramp surface ( 9 ) on its end facing the braces ( 2 ), which ramp surface causes the braces ( 2 ) to expand by an axial displacement relative to the braces ( 2 ), and at least one stop ( 10 ) cooperating with the hollow-cylindrical part ( 1 ) in the expanded position. The guide wire ( 4 ) carries a further stop ( 7 ) which cooperates with a counter stop surface ( 8 ) of the locking member ( 3 ), or a stop surface of the hollow-cylindrical part ( 1 ), upon displacement of the guide wire ( 4 ).

[0001] The invention relates to a vascular anchoring device intended tobe introduced into a blood vessel by a catheter and including bracesthat are expandable in the radial direction.

[0002] In order to position intravascular surgical tools or treatmentaids, catheters are usually employed, which enable the expansion ofblood vessels by arranging balloons of a balloon catheter or theinsertion of stents or surgical tools for operative interventions intoblood vessels. As a rule, the catheter is introduced via a blood vesselsuch as, for instance, the femoral artery or the brachial artery inorder to render feasible the required treatment on the respective site.Such an intervention, however, always entails the risk of particles and,in particular, plaque particles being released from the vessel wall intothe bloodstream, thus causing damage and, in particular, embolisms andhence an interruption or throttling of the blood supply to the targettissue. It has, therefore, been already suggested in this context to usefilter systems that are capable of capturing the particles releasedduring an intervention. Known filtering systems as are described, forinstance, in U.S. Pat. No. 5,300,086 comprise braces which areexpandable in the radial direction and between which a filter materialcan be tentered radially. In that known device, the braces are designedto be biased in the radial direction and maintained in the foldedposition by a cladding hose which is introduced together with the guidewire and the filter. By retracting the cladding hose, it is subsequentlyfeasible to move the braces outwards under the biasing force. Whenfixing such braces in a blood vessel, the guide wire is, however, nolonger freely movable and, in particular, no longer movable in the axialdirection beyond the site on which the radially expandable braces are incontact with the vessel wall. The bracing force is limited by theelastic prestress of the braces. In order to retract or fold theseradially expanded braces, a hose-like applicator can again be lappedover the braces to effect their inward movement against the biasingforce or the spring force of the braces, respectively. While the bracesare opened by a tensile movement, their closure is effected by a thrustmovement of the actuation member in the opposite direction.

[0003] From FR-2 580 504 A, a device for positioning an intravascularfilter is, moreover, known. In that device, a blood filter capable ofbeing inserted by means of a catheter and a guide wire and reversiblyexpanded by means of an inflatable balloon is described, which can beanchored within a vein. The blood filter is comprised of severalflexible arms.

[0004] The invention aims to provide a retractable vascular anchoringdevice of the initially defined kind, which enables both opening andclosing each by a tensile movement in the same direction, and whichfurther ensures as free a movability of the guide wire as possiblebeyond the anchoring site after a defined outward movement and anchorageof the braces.

[0005] To solve this object, the anchoring device according to theinvention essentially consists in that the anchoring device comprises asubstantially hollow-cylindrical part including axially extending bracesdeparting from an end side, and a locking member coaxially guided withinthe hollow-cylindrical part along a guide wire of the catheter, that thelocking member carries at least one ramp surface on its end facing thebraces, which ramp surface causes the braces to expand by an axialdisplacement relative to the braces, and at least one stop cooperatingwith the hollow-cylindrical part in the expanded position, and that theguide wire carries a further stop which cooperates with a counter stopsurface of the locking member, or a stop surface of thehollow-cylindrical part, upon displacement of the guide wire. Due to thefact that the anchoring device comprises a substantiallyhollow-cylindrical part including axially extending braces departingfrom an end side, and a locking member coaxially guided within thehollow-cylindrical part along a guide wire of the catheter, it hasbecome feasible to provide an outward movement of the braces through arelative displacement of the locking member relative to the partcarrying the braces, for instance by simply retracting the guide wire,to which end the configuration is devised such that the locking memberwhich is axially displaceable along the guide wire carries at least oneramp surface on its end facing the braces, which ramp surface causes thebraces to expand due to an axial displacement relative to the braces. Tothis end, it is merely required to appropriately secure thehollow-cylindrical part carrying the braces against displacement, whichis readily feasible by the aid of an applicator in the form of a hoseslipped over the guide wire. By retracting the guide wire, a stopprovided on the guide wire is brought into active connection with thelocking member and displaces the locking member relative to thehollow-cylindrical part, thus causing the braces to expand on account ofthe ramp surfaces. When kinematically reversing this movement, a stop ofthe guide wire is able to cooperate with the structural componentcarrying the braces, while the applicator cooperates with the lockingmember. By the locking member carrying at least one stop cooperatingwith the hollow-cylindrical part in the expanded position, the lockingmember can be retracted into the respective position in which a definedexpanded position is assumed by the braces and locking of the expandedposition is simultaneously ensured by the stop preventing a newdisplacement of the locking member-opposite to the direction ofdisplacement of the guide wire. Such stops can be formed by surfaces ofany desired shape, which cooperate in the axial direction such as, e.g.,grooves, holes, tongues or the like. Under those circumstances,automatic locking is, thus, ensured with the guide wire retaining itsfree axial displaceability at least to the extent that the stop of theguide wire will not collide with the locking member or the structuralcomponent carrying the braces. For the automatic closure of theexpandable braces and the detachment of the anchorage, the lockingmember can subsequently be retracted beyond the locking position bynewly applying the hose-like applicator through movement in the samedirection, which will again result in the automatic inward movement ofthe substantially axially extending, yet radially outwardly movedbraces, due to the elasticity of the hollow-cylindrical part. The inwardmovement in a particularly advantageous manner can be facilitated inthat, as in correspondence with a preferred embodiment of the invention,the braces are encompassed by a ring of elastomeric material. Theexpansion or extension of the braces in the radial direction can bepromoted by designing the ramp surfaces as wedge or conical surfaces.

[0006] Such a configuration, therefore, provides a kinematics by whichan expansion of the braces is initially effected via the ramp surfaces,which may be designed as wedge, annular bead or conical surfaces, forinstance by the retraction of the guide wire under the collision of theguide wire stop with the locking member, and the inward movement of thebraces is subsequently enabled by further retraction of the guide wire,i.e. movement in the same sense, while entraining the locking member.

[0007] The anchoring device can be employed for any desired applicationand, while fully maintaining the functionality of the guide wire, offersthe essential advantage of providing a defined anchoring site relativeto which, or on which, further auxiliary means can be arranged. Thus, itis feasible to introduce, along the guide wire, to the treatment sitethe balloons of a balloon catheter or stents or surgical instrumentsrequired for the intravascular intervention, wherein it is, of course,also feasible in a particularly simple manner to use the anchoringdevice for tentering a filter.

[0008] Additional treatment aids such as, for instance, means for dosingin drugs can be readily coupled with the anchoring device, to which endthe configuration advantageously is devised such that the end of thehollow-cylindrical part facing away from the braces carries couplingmembers and, in particular, magnetic or latchable coupling members. Suchcoupling members which enable detachable coupling and hence uncouplingalso allow for the appropriate dislocation of the anchor by means ofsuitable coupleable applicators with the braces retracted.

[0009] In order to facilitate the introduction of the braces and thewithdrawal of the newly retracted braces, the configuration preferablyis devised such that the braces are designed as fingers following thehollow-cylindrical part and bent or curved in the axial direction.

[0010] Overall, a positionable and detachable vascular anchoring deviceis, thus, provided, which can be introduced and fixed on the desiredsite by particularly simple means, its installation and removal being,for instance, feasible by a simple tensile movement without reversal ofthe direction of movement of the guide wire. At the same time, as largea movability and displaceability of the guide wire as possible aresafeguarded for subsequent operations in a given position of theanchoring device, thus substantially facilitating intravascularinterventions. Intravascular treatments can be carried out in bloodvessels according to standards via balloons and/or stents or the like,which are introduced by means of a guide wire, while the capture ofparticles released during an intervention is simultaneously feasiblewhen using the anchoring device as a filter. The anchoring device in aparticularly advantageous manner may be made of materials which arevisible under X-rays and, for instance, comprise metallic filter fingersso as to enable the safe pursuit of the respective position.

[0011] In the following, the invention will be explained in more detailby way of an exemplary embodiment schematically illustrated in thedrawing. Therein,

[0012]FIG. 1 is a cross-sectional view through the anchoring deviceaccording to the invention with extended braces; and

[0013]FIG. 2 is a cross-sectional view analogous to FIG. 1 with foldedbraces.

[0014]FIG. 1 depicts a substantially cylindrical base body 1, whichcomprises braces 2 provided on its end side. The substantiallycylindrical base body 1, together with a locking member 3, is eachguided concentrically with a guide wire 4 so as to be displaceable inthe axial direction of the same. Its introduction is effected via anapplicator schematically indicated at 5, which is slipped over the guidewire 4 in the manner of a flexible hose, thus cooperating with the endface 6 of the hollow-cylindrical part 1, that faces away from the braces2. In the folded position of the braces, the hollow-cylindrical part 1together with the braces can, thus, be placed into the respectiveposition by means of the applicator 5. By retracting the guide wire 4,it is feasible to bring into active connection with the end face 8, or astop of the locking member 3 projecting in the axial direction, a stop 7provided on the guide wire, thus causing the locking part 3 to beretracted under expansion of the braces 2. The expansion of the braces 2is effected via ramp surfaces 9 of the locking member, which aredesigned as conical surfaces. The locking member 3 carries at least oneelastically unfoldable or deformable stop 10, which is able to cooperatewith the hollow-cylindrical part 1 in different positions. To this end,annular grooves 11 are provided, whereby the elastically deformable stop10 is able to latch in one of these annular grooves 11, thus causing thebraces 2 to assume a defined expanded position. The annular grooves 11may be replaced with openings such as, e.g., slots or holes, wherein,with the kinematics reversed, annular grooves, slits or holes providedin the locking member 3 are naturally able to cooperate with accordinglyelastically deformable stops 10 provided on the hollow-cylindrical part1. With the braces completely extended, the unfoldable stop 10illustrated engages from behind the end face 6 of the hollow-cylindricalpart, that faces away from the braces, locking being feasible indifferent expanded positions of the braces 2. After the braces 2 havebeen locked and extended, the applicator 5 can be removed again and theguide wire 4 can be displaced in the axial direction, which displacementis limited merely by the fact that the stop 7 of the guide wire 4 cannotbe retracted beyond the stop 8 of the locking member 3 upon positioningof the anchoring device.

[0015] On its end facing away from the braces, the locking part 3 maycarry coupling members schematically indicated at 12, to whichadditional means can be coupled.

[0016] In order to unlock the anchoring device, the applicator 5 can benewly slipped on and cooperate with the end face 6 of thehollow-cylindrical part. As the guide wire 4 is subsequently pulled backin the sense of arrow 13, the part carrying the ramp surfaces 9 entersthe hollow-cylindrical part 1 under elastic deformation of the latter,thus causing the braces 2 to again move radially inwards and get out ofengagement with the vessel wall. This inward movement can be promoted byan elastomeric ring 14, which is apparent, in particular, from FIG. 2.In that inwardly folded position of the braces 2, it is again feasibleto completely retract the anchoring device without entailing any risk ofinjury to the blood vessel.

[0017] The braces 2 may be connected with a filter not illustrated inthe Figures, which can be tentered over the total cross section of theblood vessel with the braces being positioned as illustrated in FIG. 1.

1. A vascular anchoring device intended to be introduced into a bloodvessel by a catheter and including braces that are expandable in theradial direction, characterized in that the anchoring device comprises asubstantially hollow-cylindrical part (1) including axially extendingbraces (2) departing from an end side, and a locking member (3)coaxially guided within the hollow-cylindrical part (1) along a guidewire (4) of the catheter, that the locking member (3) carries at leastone ramp surface (9) on its end facing the braces (2), which rampsurface causes the braces (2) to expand by an axial displacementrelative to the braces (2), and at least one stop (10) cooperating withthe hollow-cylindrical part (1) in the expanded position, and that theguide wire (4) carries a further stop (7) which cooperates with acounter stop surface (8) of the locking member (3), or a stop surface ofthe hollow-cylindrical part (1), upon displacement of the guide wire(4).
 2. A vascular anchoring device according to claim 1, characterizedin that the ramp surface (9) is designed as a wedge surface, an annularbead surface or a conical surface.
 3. A vascular anchoring deviceaccording to claim 1 or 2, characterized in that the braces (2) areencompassed by a ring (14) of elastomeric material.
 4. A vascularanchoring device according to claim 1, 2 or 3, characterized in that theend of the hollow-cylindrical part (1) facing away from the braces (2)carries coupling members (12) and, in particular, magnetic or latchablecoupling members.
 5. A vascular anchoring device according to any one ofclaims 1 to 4, characterized in that a filter capable of being tenteredover the expanded cross section is connected with the braces (2).
 6. Avascular anchoring device according to any one of claims 1 to 5,characterized in that the braces (2) are designed as fingers followingthe hollow-cylindrical part (1) and bent or curved in the axialdirection.